Connected: An Internet Encyclopedia
RFC 1902 - 9. Refined Syntax

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### 9. Refined Syntax

Some macros have clauses which allows syntax to be refined, specifically: the SYNTAX clause of the OBJECT-TYPE macro, and the SYNTAX/WRITE-SYNTAX clauses of the MODULE-COMPLIANCE and AGENT- CAPABILITIES macros [2]. However, not all refinements of syntax are appropriate. In particular, the object's primitive or application type must not be changed.

Further, the following restrictions apply:

                                Restrictions to Refinement on
      object syntax         range   enumeration     size    repertoire
      -----------------     -----   -----------     ----    ----------
                INTEGER      (1)        (2)           -         -
              Integer32      (1)         -            -         -
             Unsigned32      (1)         -            -         -
           OCTET STRING       -          -           (3)       (4)
      OBJECT IDENTIFIER       -          -            -         -
                   BITS       -         (2)           -         -
              IpAddress       -          -            -         -
              Counter32       -          -            -         -
              Counter64       -          -            -         -
                Gauge32      (1)         -            -         -
              TimeTicks       -          -            -         -

where:

1. the range of permitted values may be refined by raising the lower- bounds, by reducing the upper-bounds, and/or by reducing the alternative value/range choices;

2. the enumeration of named-values may be refined by removing one or more named-values (note that for BITS, a refinement may cause the enumerations to no longer be contiguous);

3. the size in characters of the value may be refined by raising the lower-bounds, by reducing the upper-bounds, and/or by reducing the alternative size choices; or,

4. the repertoire of characters in the value may be reduced by further sub-typing.

Otherwise no refinements are possible. Further details on sub-typing are provided in Appendix C.

Next: 10. Extending an Information Module

Connected: An Internet Encyclopedia
RFC 1902 - 9. Refined Syntax